In recent years, optical fibers have come to be widely used as a communication path. In communication by optical fibers, transmission of large volumes of information is possible. At the present, with the development of multimedia and transmission of a variety of information as digital information on a world-wide scale, optical fibers have come to be used as the preferred communication path.
Thus, it is not difficult to imagine that the use of optical fibers as communication paths will flourish in the future.
One important factor when using optical fibers as a communication path is the light source, in particular, for example, the precision of a pulse light source. One important factor related to the precision of the light source is that the wavelength of the light emitted does not vary with changes in the environment (for example, changes in temperature, etc.).